1 /* $NetBSD: mount_union.c,v 1.8 2002/09/21 18:43:38 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1992, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software donated to Berkeley by 8 * Jan-Simon Pendry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 __COPYRIGHT("@(#) Copyright (c) 1992, 1993, 1994\n\ 42 The Regents of the University of California. All rights reserved.\n"); 43 #endif /* not lint */ 44 45 #ifndef lint 46 #if 0 47 static char sccsid[] = "@(#)mount_union.c 8.6 (Berkeley) 4/26/95"; 48 #else 49 __RCSID("$NetBSD: mount_union.c,v 1.8 2002/09/21 18:43:38 christos Exp $"); 50 #endif 51 #endif /* not lint */ 52 53 #include <sys/param.h> 54 #include <sys/mount.h> 55 56 #include <miscfs/union/union.h> 57 58 #include <err.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 #include <util.h> 64 65 #include "mntopts.h" 66 67 static const struct mntopt mopts[] = { 68 MOPT_STDOPTS, 69 MOPT_GETARGS, 70 { NULL } 71 }; 72 73 int main __P((int, char *[])); 74 int mount_union __P((int argc, char **argv)); 75 static int subdir __P((const char *, const char *)); 76 static void usage __P((void)); 77 78 #ifndef MOUNT_NOMAIN 79 int 80 main(argc, argv) 81 int argc; 82 char **argv; 83 { 84 return mount_union(argc, argv); 85 } 86 #endif 87 88 int 89 mount_union(argc, argv) 90 int argc; 91 char *argv[]; 92 { 93 struct union_args args; 94 int ch, mntflags; 95 char target[MAXPATHLEN]; 96 97 mntflags = 0; 98 args.mntflags = UNMNT_ABOVE; 99 while ((ch = getopt(argc, argv, "bo:r")) != -1) 100 switch (ch) { 101 case 'b': 102 args.mntflags &= ~UNMNT_OPMASK; 103 args.mntflags |= UNMNT_BELOW; 104 break; 105 case 'o': 106 getmntopts(optarg, mopts, &mntflags, 0); 107 break; 108 case 'r': 109 args.mntflags &= ~UNMNT_OPMASK; 110 args.mntflags |= UNMNT_REPLACE; 111 break; 112 case '?': 113 default: 114 usage(); 115 /* NOTREACHED */ 116 } 117 argc -= optind; 118 argv += optind; 119 120 if (argc != 2) 121 usage(); 122 123 if (realpath(argv[0], target) == 0) 124 err(1, "%s", target); 125 126 if (subdir(target, argv[1]) || subdir(argv[1], target)) 127 errx(1, "%s (%s) and %s are not distinct paths", 128 argv[0], target, argv[1]); 129 130 args.target = target; 131 132 if (mount(MOUNT_UNION, argv[1], mntflags, &args)) 133 err(1, "%s on %s", target, argv[1]); 134 if (mntflags & MNT_GETARGS) { 135 char buf[1024]; 136 (void)snprintb(buf, sizeof(buf), UNMNT_BITS, args.mntflags); 137 printf("flags=%s\n", buf); 138 } 139 exit(0); 140 } 141 142 static int 143 subdir(p, dir) 144 const char *p; 145 const char *dir; 146 { 147 int l; 148 149 l = strlen(dir); 150 if (l <= 1) 151 return (1); 152 153 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 154 return (1); 155 156 return (0); 157 } 158 159 static void 160 usage() 161 { 162 (void)fprintf(stderr, 163 "usage: mount_union [-br] [-o options] target_fs mount_point\n"); 164 exit(1); 165 } 166